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An instance where standard DMA can be used is to copy data from a
peripheral to internal memory for processor booting. With the help of the
loader tool, the tag (header information) of the boot stream is decoded to
get the storage information which includes the index, modify, and count
of a specific array to start another standard DMA.
Chained DMA. Chained DMA sequences are a set of multiple DMA
operations, each autoinitializing the next in line. To start a new DMA
sequence after the current one is finished, the IOP automatically loads
new index, modify, and count values from an internal memory location
(or external memory location for DMA to external ports) pointed to by
that channel's chain pointer register. Using chaining, programs can set up
consecutive DMA operations and each operation can have different
attributes.
The IDP port does not support DMA chaining.
Ping-pong DMA (IDP). In ping-pong DMA, the parameters have two
memory index values (index A and index B), one count value and one
modifier value. The DMA starts the transfer with the memory indexed by
A. When the transfer is completed as per the value in the count register,
the DMA restarts with the memory location indexed by B. The DMA
restarts with index A after the transfer to memory with index B is com-
pleted as per the count value. This repeats until the DMA is stopped by
resetting the DMA enable bit.
DMA Transfers Between Internal Memory
The ADSP-2136x processors can use memory-to-memory DMA to trans-
fer 64-bit blocks of data between internal memory locations.
ADSP-2136x SHARC Processor Hardware Reference
www.BDTIC.com/ADI
for the ADSP-21362/3/4/5/6 Processors
I/O Processor
2-3
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